Just bought a 89. Has engine miss and back pass side has appox 140 psi during cranking. All others are 155 to 160. New this when I bought it and it has had the recall done. Getting ready to R&R cyl head to replace head gaskets and have valves done. Sure clearance is gone. No coolant cleaning on plugs and oil is good. Has always had Mobil One. No leaks anywhere that dealer hasn't fixed. Only has 341000 on it and lower engine was done 120000 ago by the dealer. What would anybody recommend replacing while I have heads off. Injectors and or Orings, timing belt, water pump will al be replaced. Anything that could be or should be replaced at same time. Heater by pass tube for instance? Has anybody had any luck with having injectors cleaned either by running engine on pressured cleaner or sending them somewhere? How about aftermarket cams for little extra pulling power. Will be used for daily driver and pulling ATV's to hunting property.